Custom Machined Spacers

Simple Part, One Critical Dimension

A spacer just sets a gap — but that gap usually has to be exact, and across a batch every spacer has to be the same length so stacks and assemblies add up. The two things that matter are length tolerance and parallel, square faces; the bore is sized to clear the bolt or fit the shaft. It sounds trivial, and that's exactly why imprecise spacers cause so much grief downstream. We machine them to a controlled length and keep the batch consistent.

Not wheel spacers. If you searched for custom spacers meaning hub-centric wheel spacers for a car, this is not that page — specialist wheel-spacer makers in the UK do those with the right load testing. The spacers here are machined spacers to length for machines, assemblies and boards: a bore, an outside diameter and a length that no catalogue lists, from one piece, held to ±0.05 mm.

Custom Spacer Specifications

Attribute	Capability
Materials	Aluminium, steel, stainless, brass, Delrin/nylon/PTFE
Shapes	Round, hex, square, shouldered, stepped
Length tolerance	±0.02–0.05 mm (tighter on request), parallel faces
Bore	Clearance or fit to bolt / shaft
Finish	As-machined, anodize, plate, bead blast
Quantity	One-off to high-volume batch

Spacer Types We Machine

• Round bore spacers — the everyday standoff between parts
• Shouldered / stepped spacers — locating on one face
• Hex spacers — for tool grip or appearance
• Precision shim-style spacers — very tight length
• Wheel & hub spacers — automotive (see our wheel spacer case)

Spacer or Standoff — Which Do You Need?

The two get mixed up: a spacer is an unthreaded tube you pass a bolt through to set a gap; a standoff — what many catalogues sell as a threaded spacer — has an internal thread (male-female or female-female) so parts screw into it. We make both — if your part is threaded, see custom standoffs; if it's a plain through-bore, you're in the right place.

Material Choice

Metal spacers are the default wherever a bolt is torqued through them: 6061 aluminium spacers are light and cheap for general use; steel and 304 / 316 stainless steel spacers carry clamp load and resist corrosion outdoors; brass spacers machine to a fine finish and break galvanic pairs; plastics (Delrin, nylon, PTFE) insulate or run quiet. For larger plastic quantities we can mold instead of machine — part of being a full custom parts maker in any material. Tell us the bolt size, the gap you need and the load, and we'll recommend.

Spacer Weight & Material Cost — Compare Live

A spacer is a plain tube, so material choice shows up directly as weight and cost. Aluminum 6061 keeps a stack light; stainless and steel carry more load; nylon or Delrin insulate and damp. Enter the outer diameter, bore and length to compare the exact weight and relative material cost of each option:

Will it fit? Spacer checks before you order

Two numbers decide whether a spacer does its job: the length, held to ±0.02–0.05 mm with parallel faces, and the bore. A 9 mm bore on an M8 bolt lets the spacer sit 0.6 mm off centre and the joint settles when the bolt is torqued; the right clearance for M8 is 8.4 mm (ISO 273 fine), 9 mm only when the spacer must float. If the spacer locates something — a bearing, a pulley — the bore is a fit to the shaft, not a clearance, and it goes on the drawing as H7.

What do I need to fill a 23.5 mm gap on an M8 bolt?

A spacer 23.5 mm long ±0.05, 8.4 mm bore, an outside diameter that clears the parts on either side — 16 mm is usual for M8 — in aluminium, steel, stainless or Delrin according to the joint. Say whether the two faces must be parallel to the bolt axis; on a stack of spacers that is what keeps the assembly square.

Same spacer, but stepped, hexagonal, or in Delrin

A shoulder to locate in a hole, a hex outside for a spanner, Delrin or nylon for an insulating stack, a length between catalogue steps, or 500 of them — each is a variant of the same drawing, one piece and up, quoted in 12 hours.

Frequently Asked Questions